Solid state image pickup device, method of manufacturing the same, and camera

Abstract

The solid state image pickup device includes a pixel, the pixel including: a photoelectric conversion region for generating carrier by photoelectric conversion and accumulating the carrier; a carrier holding region for accumulating carrier flowing out from the photoelectric conversion region during the photoelectric conversion region generates and accumulates carrier; a source follower amplifier SF-MOS for amplifying carrier; a transfer MOS transistor Tx-MOS for transferring the carrier accumulated in the photoelectric conversion region to the source follower amplifier SF-MOS; and a transfer MOS transistor Ty-MOS for transferring the carrier accumulated in the carrier holding region to the source follower amplifier SF-MOS. The carrier holding region is formed so as to have a trench structure.

1. A solid state image pickup device comprising a pixel, the pixel comprising:
 a semiconductor substrate; 
 a photoelectric conversion region for generating carriers by photoelectric conversion and accumulating the carriers; 
 an accumulating region for accumulating the carrier generated by the photoelectric conversion; 
 a carrier holding region for accumulating carrier flowing out from the photoelectric conversion region, the carrier holding region being formed so as to have a trench structure formed in the semiconductor substrate; 
 a first transfer element for transferring the carrier accumulated in the photoelectric conversion region to the accumulating region; 
 a second transfer element for transferring the carrier accumulated in the carrier holding region to the accumulating region. 
 
     
     
       2. A solid state image pickup device according to  claim 1 , wherein the accumulating region is a floating diffusion region. 
     
     
       3. A solid state image pickup device according to  claim 1 , wherein the trench structure of the carrier holding region comprises a structure wherein a trench is formed in the semiconductor substrate, an insulating region is formed on side walls and a bottom of the trench, and an electrode member is formed in the trench. 
     
     
       4. A solid state image pickup device according to  claim 3 , wherein the trench structure is formed in a first semiconductor region of a first conductivity type, and a second semiconductor region of a second conductivity type is formed between the first semiconductor region and the insulating region, the second semiconductor region being connected to a source or a drain of a MOS transistor for reading out carrier from the carrier holding region. 
     
     
       5. A solid state image pickup device according to  claim 3 , wherein the trench structure is formed in a first semiconductor region of a first conductivity type, and a second semiconductor region of the first conductivity type is formed between the first semiconductor region and the insulating region, the second semiconductor region having an impurity concentration lower than an impurity concentration of the first semiconductor region, the first semiconductor region being connected to a source or a drain of a MOS transistor for reading out carrier from the carrier holding region. 
     
     
       6. A solid state image pickup device according to  claim 1 , further comprising a pixel signal generating region for generating a pixel signal according to carrier accumulated in the photoelectric conversion region and carrier accumulated in the carrier holding region. 
     
     
       7. A solid state image pickup device according to  claim 1 , wherein the photoelectric conversion region has an opening and the carrier holding region is shielded from light. 
     
     
       8. A camera, comprising:
 a solid state image pickup device according to  claim 1 ; 
 a lens for focusing an optical image on the solid state image pickup device; and 
 a diaphragm for varying light quantity that passes through the lens.